Means for welding pipe sections

ABSTRACT

A method and means of welding adjacent pipe sections in tandem relation at the installation site for the pipe line. An internal clamping apparatus simultaneously engages the inner periphery of adjacent pipe ends in such a manner as to apply radially outward pressure thereto for reforming the ends into substantially identical circular configurations, regardless of any existing deformation in the pipe. The two reformed pipe ends are securely retained in an abutting position by the clamping means during the entire welding operation. An external welding apparatus is secured around the outer periphery of the pipe in the proximity of the abutting pipe ends for providing a circumferential weld at the pipe joint. The welding apparatus includes a pair of independently movable carriages, with each carriage being provided with a plurality of welding heads for performing simultaneous but sequential welding operations. One of the carriages moves from a position corresponding to 0* through a distance of substantially 180* around the circumference of the pipe while the other of the carriages moves around the circumference first from a position of 270* to 180* and then from 360* back to 270* whereby the welding operation is performed in a balanced manner around the entire circumference of the pipe joint. The welding heads of each carriage perform simultaneous welding operations, with the welding head performing a first welding operation at the pipe joint, and the next succeeding welding head tracking the movement of the first welding head and performing a second welding operation at substantially the exact optimum time interval between the two welding steps to assure an efficient welding of the joint. It is preferable to provide three of the welding heads on each carriage. However, it has also been found that two welding heads on each carriage perform an efficient total welding operation. Subsequent to the welding of the pipe joint, the internal clamping apparatus and external welding apparatus may be moved longitudinally along the pipe line to the position of the next pipe joint to be welded, and the entire operation may be repeated.

tilted States Patent 91 Stanley 11 3,748,426 [451 July 24,1973

[ MEANS FOR WELDING PIPE SECTIONS [75] Inventor: Richard Carl Stanley,Tulsa, Okla.

[73] Assignee: Midwestern Specialties, Ltd., Tulsa,

Okla.

[22] Filed: Aug. 2, 1971 [21] Appl. No.: 168,078

Related U.S. Application Data [62] Division of Ser. No. 778,416, Nov.25, 1968, Pat. No.

Primary Examiner-J. V. Truhe Assistant Examiner-L. A. SchutzmanAttorney-William S. Dorman [57] ABSTRACT A method and means of weldingadjacent pipe sections in tandem relation at the installation site forthe pipe line. An internal clamping apparatus simultaneously engages theinner periphery of adjacent pipe ends in such a manner as to applyradially outward pressure thereto for reforming the ends intosubstantially identical circular configurations, regardless of anyexisting deformation in the pipe. The two reformed pipe ends aresecurely retained in an abutting position by the clamping means duringthe entire welding operation. An external welding apparatus is securedaround the outer periphery of the pipe in the proximity of the abuttingpipe ends for providing a circumferential weld at the pipe joint. Thewelding apparatus includes a pair of independently movable carriages,with each carriage being provided with a plurality of welding heads forperforming simultaneous but sequential welding operations. One of thecarriages moves from a position corresponding to 0 through a distance ofsubstantially 180 around the circumference of the pipe while the otherof the carriages moves around the circumference first from a position of270 to 180 and then from 360 back to 270 whereby the welding operationis perfonned in a balanced manner around the entire circumference of thepipe joint. The welding heads of each carriage perform simultaneouswelding operations, with the welding head performing a first weldingoperation at the pipe joint, and the next succeeding welding headtracking the movement of the first welding head and performing a secondwelding operation at substantially the exact optimum time intervalbetween the two welding steps to assure an efficient welding of thejoint. It is preferable to provide three of the welding heads on eachcarriage. However, it has also been found that two welding heads on eachcarriage perform an efficient total welding operation. Subsequent to thewelding of the pipe joint, the internal clamping apparatus and externalwelding apparatus may be moved longitudinally along the pipe line to theposition of the next pipe joint to be welded, and the entire operationmay be repeated.

8 Claims, 22 Drawing Figures PATENTED M245!" 3. 748.426

sum 01 or 1 ATTORNEY PAI ENIEU Jul 24 3.748.426

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sum 13 or 13 INVENTOR. RICHARD C. STANLEY ATTORNEY MEANS FOR WELDINGPIPE SECTIONS This application is a division of my co-pendingapplication Ser. No. 778,416, filed Nov. 25, 1968, now US. Pat. No.3,681,560, issued Aug. 1, 1972.

This invention relates to improvements in pipe welding method and meansand more particularly, but not by way of limitation, to a novel methodand means for internal clamping of adjacent pipe ends and externalcircumferential welding of the pipe joint.

Pipe lines normally extend throughout relatively long distances andacross terrain which is often remote. In the usual construction of apipe line, a plurality of pipe sections are initially disposed in tandemrelation, and the adjacent ends of the pipe sections are placed inabuttment and welded together. Of course, it is important that thewelded joints be of an extremely high quality to assure an efficienthandling of the products transported thereby, and to increase the lifeof the pipe line while reducing maintainence thereof. The welding of thepipe joints in the field has long been a problem in the industry, andmuch time and expense has been involved in an effort to solve theproblem.

The present invention contemplates an improved method and means forwelding pipe joints in the field, and includes two complementary overallsteps for providing the increased welding efficiently at each joint.First, an internal pipe clamping apparatus has been particularlydesigned and constructed for simultaneously applying radially outwardpressure on each of the abutting pipe ends for restoring a substantiallytrue circular configuration for the pipe ends to be united or welded.The clamping apparatus forms the pipe ends into a substantiallyidentical configuration and securely holds the ends so formed in anefficient abutting position during the welding operation. An externalwelding apparatus is then utilized for providing a circumferentialwelding operation around the joint determined by the abutting pipe ends.The welding apparatus is provided with a pair of carriages independentlymovable around the circumference of the pipe. Each carriage is providedwith a plurality of aligned welding heads so mounted on the respectivecarriage whereby one of said heads applies an initial layeror weldingmaterial in the pipe joint, and the next succeeding welding head appliesthe next succeeding layer of welding material on the first appliedlayer, with the time interval between the two layers being at theoptimum for assuring an efficient overall welding operation.

In addition, each of the carriages move separately about thecircumference of the pipe for performing simultaneous welding operationsat different positions in the pipe joint. One of the carriages initiallyis positioned at and moves around the circumference to a position ofapproximately 180 during the welding operation. Simultaneously, thesecond carriage is initially positioned at 270 and moves around the pipeto a position of 180 during the welding operation, then quickly moves tothe 360 and again begins the welding operation while moving from 360back to the initial 270 position. This results in a completecircumferential weld at the pipe joint, and efficiently balances thewelding apparatus at all times.

The unwelded pipe joint is usually in the form of a V- shapedcircumferential groove between the abutting ends of the pipe sectionsand the welding operation fills the groove with welding material foruniting the pipe sections. Each of the welding heads may beindependently oscillated during the welding operation for increasing theoverall results of the apparatus and method. The welding head providingthe first pass" or application of welding material in the bottom of thegroove is oscillated in a relatively slight movement whereas the nextsucceeding welding headis oscillated in a greater movement. Each weldinghead may be suitably adjusted whereby the oscillation thereof will be atthe optimum in accordance with the particular welding requirementsthereof. In addition, the plane of the weld groove may notbe exactlyperpendicular to the longitudinal axis of the pipe, or indeed, maydeviate from any plane surface at all. In order to overcome thisdisadvam tage, a guide wheel is provided which rolls along or rides inthe groove and maintains the welding heads in alignment with the grooveregardless of irregularities in the path of the groove. Subsequent tothe completion of the welding at one pipe joint, the clamping apparatusand welding apparatus may be moved longitudinally through and along thepipe to the next pipe joint and the operation may be repeated.

The resulting welded joint accomplished through the method and means ofthe present invention have proven to be excellent. X-ray inspection hasshown the welded joints are substantially free from holidays andsections cut through the material of the weld and adjacent material ofthe pipe sections have shown an excellent quality in the resulting weld.It is to be noted that the superior clamping method and means forreforming the adjacent pipe ends and aligning and clamping the pipe endsin abutting relationship prior to and during the welding operation arean important step in the overall results obtained in the final weldingoperation. Any misalignment of the abutted pipe ends or anynonconforrnity therebetween would decrease the end result of the weldingoperation. Thus, the novel and increased efficiency of results possiblethrough practice of the present invention include the combined steps ofperforming the pipe ends into a substantially circular configuration bythe internal clamping means, efficient aligning and clamping theabutting pipe ends prior to and during the welding operation, andperforming the external welding operation by simultaneously andsequentially welding the joint in separate welding layers or operationswhile passing a plurality of welding heads circumferentially around thepipe joint. The novel method and means for welding pipe sections issimple and efficient in operation and economical and durable inconstruction.

It is an important object of this invention to provide a novel methodand means for welding pipe joints which provides an optimum weld at thepipe joint inan efficient and economical manner.

Another object of this invention is to provide a novel method and meansfor welding pipe joints wherein the adjacent pipe ends to be welded areinitially formed into substantially true mating circular configurationsfor improving the overall welding results.

It is another object of this invention to provide a novel method andmeans of welding a pipe joint wherein the welding operation isaccomplished by a multiple step welding process with each welding stepbeing accomplished in a sequential and simultaneous relationship withthe other welding steps.

A further object of this invention is to provide a novel method andmeans of welding a pipe joint wherein the welding operation isaccomplished through sequential and simultaneous operation ofindependent welding heads, with each welding head being independentlyoscillated in accordance with the desired performance thereof forincreasing the overall welding results.

Still another object of this invention is to provide a novel method andmeans of welding a pipe joint wherein the welding heads are maintainedin substantial alignment with the weld groove during the weldingoperation.

A still further object of this invention is to provide a novel methodand means of welding a pipe joint wherein the abutting pipe ends aresecurely clamped and aligned prior to and during the welding operation.

It is a still further object of this invention to provide a novel methodand means of welding a pipe joint wherein two sets of welding heads areindependently moved circumferentially around the pipe joint forperforming the welding operation in a balanced welding operation.

Other and further objects and advantageous features of the presentinvention will hereinafter more fully appear in connection with adetailed description of the drawings in which:

FIG. 1 is a side elevational view of a pipe welding apparatus embodyingthe invention.

FIG. 2 is a front elevational view of a pipe welding apparatus embodyingthe invention with certain portions eliminated for purposes ofillustration.

FIG. 3 is a rear elevational view of a pipe welding apparatus embodyingthe invention and disposed around a pipe section with the pipe beingdepicted in dotted lines.

FIG. 4 is a side elevational view of the track and saddle member of apipe welding apparatus embodying the invention.

FIG. 5 is a plan view of a portion of the support structure for thewelding heads.

FIG. 6 is a side elevational view of a portion of the support structureshown in FIG. 5 and particularly indicates the adjusting mechanism forthe welding apparatus.

FIG. 7 is a perspective view of a support base member utilized in theinvention.

FIG. 8 is an enlarged elevational view particularly depicting the guidewheel means in association with a welding head.

FIG. 9 is an elevational view of the yieldable attaching means for theguide roller of the welding apparatus.

FIG. 10 is a sectional view taken on line 10-10 of FIG. 9 depicting theadjusting arrangement for the guide roller mechanism of the weldingapparatus.

FIG. 11 is a bottom view of a support member of the welding apparatus.

FIG. 12 is a sectional view taken on line 12-12 of FIG. 11.

FIG. 13 is an enlarged sectional view taken on line 13-13 of FIG. 6.

FIG. 14 is a sectional elevational view of a pipe section having aninternal clamping apparatus member the invention disposed therein.

FIG. 15 is a transverse sectional view of a pipe section having aninternal clamping apparatus member the invention disposed therein.

FIG. 16 is a composite transverse sectional view of a pipe sectionhaving the clamping mechanism disposed therein with the lower right handportion of the figure depicting a clamp as modified for large diameterpipe sections.

FIG. 17 is a sectional view taken on line 17-17 of FIG. 16 and depictingthe clamping portion of the clamping apparatus disposed at the jointwith the upper half of the figure depicting the clamp in a clampingposition and the lower half of the figure depicting the clamp in arelaxed position.

FIG. 18 is a side elevational view of a roller member of the clampingapparatus for propelling the clamping apparatus through the interior ofthe pipe.

FIG. 19 is a plan view of the roller depicted in FIG. 18.

FIG. 20 is a view taken on line 20-20 of FIG. 18.

FIG. 21 is a sectional view taken on line 21-21 of FIG. 14. 1

FIG. 22 is an elevational view of a pipe joint with a schematicdepiction of an internal clamping apparatus, an external weldingapparatus in association therewith embodying the invention.

Referring to the drawings in detail, and particularly FIGS. 1 through13, an external pipe welding apparatus in generally indicated at 10which comprises a plurality of welding heads 12 adjustably mounted on acarriage device 14 in a manner as will be hereinafter set forth. Thecarriage device 14 is movably secured or mounted on a circular orannular track 16 which encircles a pipe section 18, or other tubularmember, or the like. The track 16 is carried by or secured to a saddlemember 20 which straddles a portion of the outer periphery of the pipe18 and secures the track 16 thereon in a manner precluding rotation ofthe track 16 with respect to the longitudinal axis of the pipe 18. Thecarriage 14 moves or is propelled around the track 16 during a pipejoint welding operation for moving the welding heads 12 around the pipefor providing a circumferential, in place, welding operation, as will behereinafter set forth.

The pipe welding apparatus 10 as depicted herein preferably comprisesthree welding heads 12a, 12b, and 12c, as particularly shown in FIG. 2.However, it is to be noted substantially any desired number of weldingheads may be used. By way of example, an efficient welding operation hasbeen performed utilizing two welding heads following the same generalprocedure as will be hereinafter set forth. The welding heads 12a, 12b,and may be of any suitable type and as shown herein are of the MIG(metallic inert gas) type.

The welding heads 12 are each independently mounted on a base membergenerally indicated at 22 whereby the position of each welding head 12may be independently adjusted and each head 12 may be independentlyoscillated during the welding operation for a purpose and in a manner aswill be hereinafter set forth. The base 22 is bolted or otherwisesecured to a pair of shoulder blocks 24 and 26 which are suitablysecured to the inner faces of a pair of spaced side plates 28 and 30having a rear or back filler plate secured therebetween. The shoulderblocks 24 and 28 extend inwardly from the side plates 28 and 30 asparticularly shown in FIG. Sand the base 22 is provided with upstandingboss or flange portions 32 and 34 extending along the opposite edgesthereof as viewed in FIG. 7 whereby bolts or the like 36 may be utilizedfor securing the base 22 to the shoulders 24 and 26 and between the sideplates 28 and 30. In addition, a pair of spaced upwardly extending blockmembers 38 and 40 are provided on the upper surface of the base member22 as viewed in FIGS. 5 and 7 whereby bolts 42 or the like, may beutilized for facilitating securing of the base 22 to the shoulders 24and 28. The shoulders 24 and 26 each support a suitable control motor 44and 46 respectively and a third similar control motor 48 is interposedtherebetween and supported on a plate 50 which is bolted or otherwisesecured on the blocks 38 and 40, such as by the bolts 52. The motors 44,46, and 48 may be of any suitable type and are preferably a Boehmcontrol motor which is utilized for oscillating the welding heads 12 aswill be hereinafter set forth.

The base 22 is provided with a plurality (preferably three) of recesses54a, 54b, and 54c as particularly shown in FIG. 7 disposed insubstantial alignment with the welding heads 12a, 12b, and 12c,respectively, the recesses 54a, 54b, and 54c being provided for slidablyreceiving the welding head support apparatus 56 of the respectivewelding head. Each support member 56 for the welding heads 12 issubstantially identical and only one of the support structures 56 willbe set forth in detail herein. whereby the welding heads 12 may beadjustably secured to the base 22 in any suitable manner, the securingdevice 56 depicted herein comprises a substantially tubular split nozzleclamp 58 adapted to be secured around the welding head or welding nozzle12. A radially outwardly projected rodor arm member 62 is carried by theclamp 58 and extends from the clamp 58 into connection with a slidingblock member 64. The sliding block member 64 is provided with atransversely extending recess 66 for receiving a complementary flangemember 68 provided on a substantially L-shaped bracket member 70. Thesliding block 64 may be positioned with respect to the flange 68 asdesired for locating the lateral position of the respective welding head12 with respect to the pipe 18 and the block 64 may then be securelylocked in position by means of a cap screw 72 or the like which extendsthrough the bracket 70 and into engagement with the block 64.

A rod member 74 is secured to the bracket 70 and is journalled within anoscillator clamping bracket 76. The bracket 76 is preferably of thesplit sleeve type and may be secured around the rod 74 by means of thescrews 78 or the like. A plate member 80 is secured to the upper end orupper portion of the clamp 76 as viewed in FIG. 6 and is suitablydisposed within longitudinally extending grooves or recesses (not shown)provided in downwardly extending blocks or hanger members 82 which aresecured in the opposite longitudinal side walls of the respective recess54. The blocks or hangers 82 are preferably constructed from Micarta andmay be secured within the respective recess 54 in any suitable mannersuch as by bolting or the like and the plate 80 is longitudinallyslidable with respect thereto. The rod 74 may be pivotally adjustedwithin the clamp member 76 to provide the desired angular position forthe respective welding head 12 with respect to the pipe 18 and the rod74 may then be securely clamped in the selected position by the screwmember 78 as is well known.

A rod 84 is carried by the plate 80 and extends downwardly therefrom asviewed in FIG. 6. A substantially spherical ball joint member 86 isjournalled on the rod 84 and a nut 88 is threadedly secured to the outerextremity of the shank 84 for precluding accidental loss of the balljoint 86. A projection member 90 extends from the ball joint intoengagement with the opposite end of the rod 74. An internally threadedsleeve 92 bears against the outer periphery of the ball joint 86 or issuitably connected thereto and extends in a direction away from the rod84 which is opposite from the heads 12. A threaded insert member 94extends into the sleeve 92 and is carried by a substantially sphericalball joint 96. The ball joint 96 is journalled on a crank pin member 98which is carried by a crank arm follower 100 (FIG. 13) which in turn iscarried by a crank shaft 102 which extends through an aperture 104provided in the base member 22. The crank shaft 102 may be journalledwithin the aperture 104 in any suitable manner and is shown in FIG. 13.A pair of aligned bushing sleeves 106 and 108 are disposed around theouter periphery of the crank shaft 102 and provide an inner race for apair of suitable spaced ball bearings 1 l0 and 1 12 which are disposedwithin a flanged sleeve 114 secured within the aperture 104 by a lockwasher 116.

A suitable sprocket 118 is keyed or otherwise secured to the upper endof the crank shaft 102 as viewed in the drawings for transmittingrotation to the crank shaft. Whereas the sprocket may be of any suitabletype, it is preferable to provide a single structure sprocketcomplementary to a similar sprocket 120 secured to a rotatable driveshaft 122 which extends from a suitable gear boss 124 wherein the driveshaft 122 is coupled with the drive shaft (not shown) of the motor 44whereby the drive shaft 122 will be driven or rotated by the motor 44.Rotation is transmitted from the sprocket 120 to the sprocket 118 by asuitable chain, belt, or the like (not shown) as is well known. Uponactuation of the motor 44, rotation is transmitted from the sprocket 120to the sprocket 118 for rotating the crank shaft 102 whereby the crankpin 98 is rotated in a cam action as is well known for transmittingoscillatory or reciprocal motion to the plate 88 through the connectionmembers 94, 92, and 88. Of course, the length of the stroke oroscillatory movement of the plate 80 may be adjusted by the threadedconnection between the sleeve 92 and pin 94. This oscillatory motion istransmitted to the clamping member 58 and, of course, to the weldinghead 12 carried thereby. It will be apparent that the frequency andmagnitude of the oscillation of each welding head 12 may beindependently adjusted to provide the optimum welding operation in asequential welding process as will be hereinafter set forth.-

Referring now to FIGS. 1 and 2 a motor mounting bracket 126 is securedbetween the side plates 28 and 30 and is provided with a suitable wireguide connector bracket or block 128 for each welding head 12. Theconnector bracket 128 is preferably the well known or standard Aircoconnector block whereby the usual curved arcuate wire guide tubing 130may be secured or connected between the welding head nozzles and therespective connector blocks. A connecting arm 132 is suitablyv securedto the bracket 126 in association with each connector block 128 andextends in opposite directions therefrom for rotatably supporting a wirespool assembly 134 whereby welding wire may be directed from the spool134 through the connector blocks 128 and through the welding tube guide130 to the welding nozzles as is well known. In addition, a suitablemotor 136 is mounted on the mounting bracket 126 in association witheach wire spool assembly 134 for driving or feeding the wire to thewelding nozzles during a welding operation, as is well known. Of course,the motors 136 may be of any well known type, and as shown herein arepreferably of the type known as a Boehm wire feed motor.

The base 22 is movably secured to the carriage device 14 whereby thebase 22 and elements carried thereby may be adjusted to substantiallyany desired spacing from the carriage 14. An arm member 138 is providedon the carriage device 14 and extends outwardly therefrom in a directiontoward the base 22, as particularly shown in FIG. 1. The arm 138 isprovided with an elongated cam recess 140 for receiving a roller member142 therein, said roller 142 being journalled in a downwardly extendingflange 144 provided on the lower surface of the base 22 as viewed inFIGS. 2 and 5. The roller member 142 normally rides freely within therecess 140 and may be securely locked in substantially any desiredposition therein by any suitable locking means, such as by the lockingmeans generally indicated at 146 in FIG. 1 for locking the assemblyduring shipping or transporting of the device between joints to bewelded.

A downwardly extending boss 148 is provided on the lower surface of thebase 22 as viewed in the drawings, and extends along the side edgethereof oppositely disposed from the arm 138. The boss 148 is providedwith a centrally disposed bore 150 extending longitudinally therethroughas particularly shown in FIGS. 11 and 12. A plurality of spaced bushingor bearing sleeves 152 and 154 are disposed within the bore 150 and arepreferably spaced apart by a spacer sleeve 156, and retained within thebore 150 by suitable lock washers 158, or the like, as is well known. Aplurality of balls 158 are disposed within each sleeve 152 and 154 andare interposed between the sleeves 152 and 154 and a slidable shaft 160extending longitudinally through the sleeves. The balls 158 are retainedin position in any well known manner, such as by the retainer rings 162.An enlarged head member 164 is secured to the outer end of the shaft 160and is bolted, or otherwise secured to the carriage device 14, andremains immovable with respect thereto. It will be apparent that theboss 148 is freely slidable along the shaft 160, thus facilitatingmoving of the base 22 in directions toward or away from the carriagedevice 14.

A pipe joint to be welded, such as shown at 166 in FIGS. 1 and 22, isformed between the abutting ends of adjacent pipe sections 18 disposedin substantial longitudinal alignment. The ends of the pipe sections 18are normally bevelled, as is well known, and the cross sectionalconfiguration of the pipe joint 166 is usually substantially V-shaped,as depicted herein. Referring now to FIGS. 1, 2, 8, 9, and 10, a guideroller assembly generally indicated at 168 is carried by the base member22 and comprises a guide roller or wheel member 170 having an outerperiphery of a configuration generally complementary to thecross-sectional configuration of the pipe joint 166. The guide roller orwheel 170 is provided for riding in the pipe joint 116 during a pipewelding operation for automatically retaining the welding heads 12 inalignment with the pipe joint for assuring an efficient weldingoperation in a manner as will be hereinafter set forth. The roller 170is journalled on a shaft or pin 172 in any suitable manner, such as by aroller bearing 174, and is retained on the shaft 172 by a lock nut 176,or the like. The pin 172 is suitably secured to a guide arm 178 which ispreferably of an angular configuration as particularly shown in FIGS. 2and 9 to provide a substantially bell crank action for the support ofthe roller 170.

The guide arm 178 is pivotally secured at 180 to an arm retainer plate182, with the pivot point 180 providing a fulcrum for the arm 178. Theretainer plate 182 is carried by a sleeve or tubular member 184, and isn'gidly secured thereto in any well known manner. Upon assembly of theguide roller mechanism 168, the retainer plate 182 is preferablydisposed at an angle of approximately degrees with respect to the centerline of the pipe as incidated at A in FIG. 9. A pin 184 is secured tothe exposed surface of the retainer arm 182 and extends substantiallyperpendicularly outward therefrom for receiving one end of a suitablecompression spring 186. The opposite end of the spring 186 is anchoredat a second pin 188 provided on the exposed face of the arm 178. Thespring 186 constantly urges the arm 178 in a counterclockwise directionabout the fulcrum 180, as viewed in FIG. 9, and thus constantly urgesthe wheel 170 in a direction toward the pipe joint 166 in which it isexposed.

A locking pin 190 is slidably disposed within the central bore 192 of apin housing 194 which is threadedly secured to the arm 178 as shown inFIG. 10. The bore 192 is enlarged at 195 to provide a shoulder 196whereby a helical spring 198 is disposed around the pin 190 is containedbetween the shoulder 196 and an annular shoulder 200 on the pin 190 andthus constantly urges the pin 190 in a right hand direction as viewed inFIG. 10. A head member 202 is secured to the left hand end of the pin190 as shown in FIG. 10 for limiting the right hand movement of the pin190. In addition, the head 202 may be manually grasped for moving thepin 190 in a left hand direction against the action of the spring 195.When it is desired to release the engagement of the guide wheel with thepin joint 166, the pin may be retracted within the bore 192 and the arm178 may be pivoted in a clockwise direction as viewed in FIG. 9 wherebythe pin 190 will be moved into alignment with a bore or recess (notshown) provided in the retainer 182. The pin 190 may be disposed withinthe recess for locking the wheel 170 in a position out-of-engagementwith the pipe joint. This is particularly advantageous when the pipewelding apparatus 10 is to be moved from the site of one pipe joint 166to the site of another pipe joint 166, as will be hereinafter set forth.

The sleeve or tube member 184 is slidably disposed on a tube 204 in amanner as will be hereinafter set forth. The tube 204 is provided withan outwardly extending circumferential flange member 206 on the outerend thereof. The flange 206 is secured in any well known manner, such asthe bolts 210, to a substantially circular flange member 208 providedintegral with or rigidly secured to the base 22. The sleeve 184 isprovided with at least one longitudinally extending in the side wallthereof having one end open for receiving a guide pin 214 therein. Thepin 214 is carried by the inner sleeve 204 and cooperates with the slot212 for facilitating reciprocal movement of the outer sleeve 182 withrespect to the inner sleeve 204.

A web member 216 is rigidly secured within the inner sleeve 204 and isprovided with a central threaded bore 218 for receiving a threaded studmember 220 therethrough. The stud member 200 extends outwardly throughan aperture 222 provided in the retainer arm 182 and is rigidlyconnected with a suitable knob member 224 by a set screw 226, or thelike. An outwardly extending circumferential flange 228 is provided onthe stud member 220 and is interposed between the knob member 224 andthe threaded end portion for engaging an annular shoulder 230 providedconterminous with the bore 222 whereby the stud member 220 may berotated upon manual rotation of the knob 224, but is retained againstlongitudinal movement with respect to the outer sleeve 184 by theengagement of the shoulder 22 and flange 228, and further by theengagement of the knob 224 with the outer face of the retainer arm 182.Thus, rotation of the stud 220 in one direction will cause the stud 220and outer sleeve 184 to move in a right hand direction with respect tothe inner sleeve 204 as viewed in FIG. 10, and rotation of the stud 220in an opposite direction will cause the sleeve 184 to move in a lefthand direction with respect thereto. It will be apparent that manualrotation of the knob 224 permits an adjustment of the position of theguide wheel 170 for assuring an alignment of the wheel 170 and the pipejoining 166 during the installation of the pipe welding apparatus 10 atthe pipe joint for beginning a welding operation.

Referring now to FIGS. 1, 3, and 4, the carriage device 14 comprises asuitable support plate 240 having a pair of spaced outwardly extendingsupport arms 242 and 244 adapted to span a portion of the track 16 aswill be hereinafter set forth in detail. A plurality of bracket members146 are bolted or otherwise secured to the plate 240 in the proximity ofspaced elongated apertures 248 provided in the plate 240 as particularlyshown in FIG. 3. Each bracket 246 is provided with an arm member 250(FIG. 1) which extends through the respective aperture 248. A firstroller member 252 is suitably journalled on each bracket 246 and extendsthrough the respective slot 248 for engaging a first cylindrical portionof the track 16. The roller 252 is adjustably secured to the bracket 246for a purpose as will be hereinafter set forth. A second roller member254 is suitably journalled on the arm 250 of each bracket 246, with thesecond roller 254 being disposed in a plane substantially perpendicularwith respect to the plane of the first roller 252 whereby the secondroller engages an annular portion of the track 16 as will be hereinafterset forth.

A plurality of similar bracket members 256 are bolted or otherwisesecured to the plate 240 and spaced from the first brackets 246 asparticularly shown in FIG. 3. Each of the brackets 256 is secured in theproximity of spaced apertures 258 provided in the plate 240. Eachbracket 256 is provided with an arm member 260 (FIG. 3) which extendthrough the respective slot 258. A first roller member 262 is journalledon each of the brackets 256 and extends through the respective slot 258for engagement with a second cylindrical portion of the track 16. Theroller 262 is adjustably secured to the bracket 256 for a purpose aswill be hereinafter set forth. A second roller 263 is suitablyjournalled on the arm 260 of each bracket 256, with the plane of thesecond roller 263 being disposed substantially perpendicular withrespect to the plane of the first roller 262 whereby the second roller263 engages an annular portion of the track 16, as will be hereinafterset forth in detail.

The entire carriage 14 moves circumferentially around the track 16, andas shown herein, a motor 264 is carried by the carriage 14 for providingthe power or means for moving the carriage 14 with respect to the track16. The motor 264 may be of any suitable type, and as shown herein ispreferably the Boehm gear motor type. The motor 264 is suitably mountedon a support bracket 266 which in turn is mounted on or secured to thearm 244 of the support bracket plate 240. The output or drive shaft 268of the motor 264 drives a sprocket member 270 which is connected with apair of spaced sprockets 272 and 274 by a suitable chain 276, or thelike, (FIG. 3) which extends around the outer periphery of the sprocket270 and the sprockets 272 and 274, and over an adjustable idler sprocketdrive gear member 278. The position of the idler sprocket 278 may beadjusted as required for maintaining the proper tension in 276 forefficiently driving or rotating the sprockets 272 and 274.

Each sprocket 272 and 274 is secured to or connected with similar drivegears 280 and 282 through a drive shaft 284 and 286, respectively,whereby rotation of the sprockets 272 and 274 is transmitted to thegears 280 and 282. The gears 280 and 282 are disposed in meshingengagement with a ring gear 288 which extends around the outer peripheryof the track 16. Thus, upon rotation of the sprocket 270 by theactuation of the motor 264, the sprockets 272 and 274 will be rotated bythe drive chain 276, and rotation will be simultaneously transmitted tothe drive gears 280 and 282. The ring gear 288 is integral with orrigidly secured to the stationary track 16, and cannot rotate withrespect thereto. Thus, the rotation of the drive gears 280 and 282 whichmesh with the ring gear 288 causes the'entire carriage device 14 to movecircumferentially around the track 16. Of course, the welding heads 12are thus moved circumferentially around the track 16 and simultaneouslymoved circumferentially around the pipe 18 for performing acircumferential pipe joint welding operation, as will be more fully setforth in detail hereinafter.

The track 16 is of a generally annular configuration having an innerperiphery of a diameter greater than the diameter of the outer peripheryof the pipe 18. The track 16 is preferably severed at three spacedlocations, as indicated by the lines 290, 292, and 294 in FIG. 3, thusproviding three arcuate sections A, B, and C for the track 16. Thesection A as shown in FIG. 3 is substantially greater in circumferentiallength than the combined circumferential lengths of the sections B andC, but is not limited thereto. The sections B and C are secured to theopposite ends of the section A by suitable hinge members 296 and 298whereby the sections B and C may each be pivoted in the directionindicated by the arrows 300 and 302, respectively, for opening of thetrack 16 to facilitate installation of the device 10 around the pipesection 18. The free ends of the sections B and C meet at the line 294inthe closed position of the track 16, as shown in FIG. 3, and anysuitable locking or latching device (not shown) may be bolted across theabutting ends of the sections 8 and C, or otherwise span the ends of thesections for securely locking the track 16 in position around the pipe18.

The track 16 may be of any suitable construction, and as shown herein isprovided with an enlarged circumferential portion 304 having the ringgear 288 integral therewith or otherwise rigidly secured around theouter periphery thereof. A pair of concentrically arranged inner andouter circular or cylindrical rail members 306 and 308 are provided inthe annular member 304 and are open in a direction toward the carriagedevice 14 for receiving the rollers 252 and 262 therebetween. Therollers 252 bear against the outer periphery of the inner rail 308 andthe roller members 262 bear against the inner periphery of the outerrail 306 as the carriage device 14 moves circumferentially around thetrack 16. Of course, the pressure of the rollers 252 and 262 against therails 308 and 306, respectively, may be adjusted by adjusting theposition of the rollers extending through the respective slots 248 and258. In addition, an annular wall member 310 extends between the spacedrails 306 and 308, and the rollers 254 and 262 bear against or ridealong the right hand surface of the wall 310 as viewed in FIG. 4 as thecarriage device 14 moves circumferentially around the track 16. It willbe apparent that the rollers 252 and 262 facilitate the circumferentialmovement of the carriage device 14 around the track 16 and maintain thecarriage device 14 in the proper concentric relation in its movementaround the track 16. In addition, the rollers 254 and 263 maintain thecarrige device 14 against longitudinal or axial movement with respect tothe track 16 in one direction and facilitates retaining of the carriagedevice 14 in position on the track 16.

As particularly shown in FIGS. 3 and 4, the saddle 20 is secured to thetrack 16 and extends longitudinally outward therefrom in a directionaway from the carriage device 14 and welding heads 12. The saddle 20 maybe of substantially any suitable well known construction, and as shownherein comprises a plurality of longitudinally extendingcircumferentially spaced support posts 312 each having one end rigidlysecured to the track 16 oppositely disposed from the annular member 304.A plurality of pipe straddling angular strap members 314 are securedbetween the posts 312 in any well known manner. In addition, a pluralityof oppositely disposed downwardly extending side arm supports 316 aresecured to the posts 312 and are longitudinally spaced therealong asshown in FIG. 4. A longitudinally extending connecting strap 318 issuitably secured between the outer ends of each adjacent pair of arms316, and a roller support bracket 320 is secured to the opposed ends ofeach of the straps 318. A roller member 322 is journalled in each of thebrackets 320 and are so arranged as to roll along the outer periphery ofthe pipe section 18 in a longitudinal direction. A belt or adjustablestrap member (not shown) is normally secured between the strap member318 and around the outer periphery of the pipe 18 extending below andbetween the straps 318 for securely clamping and retaining the saddlemember 20 in position around the pipe 18, as is well known.

It is preferable to provide at least one roller 324 journalled in abracket 326 which is suitably secured to the track 16, with the roller324 being so arranged as to ride longitudinally along the outerperiphery of the pipe section 18. It is further preferable to provide atleast one similar roller (not shown) suitably secured to the outer edgeof the straddle strap 314 and arranged for disposition against the outerperiphery of the pipe in a manner similar to the roller 324. Theserollers are transport rollers and cooperate with the rollers 322 forfacilitating moving of the entire device longitudinally along the outerperiphery of the pipe 18 for a purpose and in a manner as will behereinafter set forth.

WELDING APPARATUS OPERATION When it is desired to weld a pair ofadjacent pipe sections 18 in end to end relation, such as at a pipejoint 166, the welding apparatus 10 is disposed on one of the pipesections 18 in the proximity of the pipe joint to be welded, with thewelding heads 12 disposed in substantial alignment with the pipe joint.In order to install the apparatus 10 around the outer periphery of thepipe section 18, it is preferable to open the track 16 by pivoting thetrack sections B and C in the directions indicated by the arrows 300 and302 whereby the track may be disposed around the pipe in a transversedirection. The rollers 322 and 325 of the saddle portion 20 rest on theouter periphery of the pipe 18 and support the apparatus 10 from thepipe section in such a manner that the track 16 is substantiallyconcentrically disposed with respect to the pipe section. The tracksections B and C may then be pivoted in a reverse direction for closingthereof around the pipe 18, and shown in FIG. 3, and may be latched orsecurely locked in the closed position.

The carriage device 14 may be secured to the track 16 either prior to orsubsequent to securing of the track and saddle around the pipe section,and the position of the rollers 252 and 262 with respect to the rails308 and 306, respectively, may then be adjusted to assure an efficientcontact therebetween. It is preferable to provide two of the carriagedevices 14 and associated welding heads 12 on the track 16 with one ofthe carriages 14 being disposed as shown in FIG. 3, which will behereinafter referred to as a 0 position, and with the other carriagedisposed at substantially 270 position (clockwise) with respect thereto.

The angular disposition of the welding heads 12 of each carriage device14 with respect to the pipe 18 may be adjusted as desired through thepivotal connection of the rod 74 (FIG. 6). Of course, the radialposition of the heads 12 with respect to the pipe 18 may be adjusted inthe usual manner, with the clamping member 58 being utilized forsecurely retaining the heads 12 in the desired position.

The guide wheel is disposed within the pipe joint 166 as shown in FIG.1, and the positioning of the guide wheel 170 in the pipe jointautomatically aligns the heads 12 with the pipe joint due to theconnection be tween the guide wheel and the welding heads ashereinbefore set forth. Of course, the guide wheel 170 rides in thegroove or pipe joint as the apparatus 10 revolves around the pipe 18,regardless of any deviation or irregularities of the plane of the pipejoint by virtue of the sliding connection of the base 22 with thecarriage device 14. Thus, the welding heads 12 are maintained insubstantial alignment with the pipe joint 166 as the apparatus 10 movescircumferentially around the pipe.

Each carriage 14 is propelled around the track 16 by actuation of therespective motor 264. Rotation of the drive shafts 268 of the motors 264rotates the drive gears 280 and 282 for moving the gears 278 around thering gear 288, thus moving the carriages 14 around the track 16. Ofcourse, the speed of movement of the carriages 14 may be regulated bythe speed of the motor 268, the ratio between the sprockets 270 and 272,and the ratio between the gears 280 and 282 and the ring gear 288, as iswell known. The drive gears 280 and 282 are circumferentially spaced insuch a manner that no drive connection or drive engagement is lostbetween

1. A pipe welding apparatus comprising annular track meansconcentrically disposed around a pipe section and radially spaced fromthe outer periphery thereof, carriage means movably secured to the trackmeans for moving the carriage means circumferentially around the outerperiphery of the pipe section, support means adjustably secured to thecarriage means and movable simultaneously therewith around the outerperiphery of the pipe section, multiple welding head means adjustablysecured to the support means and movable simultaneously therewith Aroundthe outer periphery of the pipe section with each welding head followingthe preceeding welding head, guide means cooperating between the supportmeans and multiple welding head means for maintaining each welding headof the multiple welding head means in substantial alignment with thepipe joint during movement thereof around the pipe section, meansprovided on the multiple welding head means for independent adjustmentof the radial position of each welding head with respect to the pipe,oscillating means cooperating with the multiple welding head means forselective oscillation of each welding head in a direction substantiallyperpendicular to the plane of the pipe joint during a welding operationwhereby a complete welding operation is performed upon a single pass ofthe multiple welding head means, actuating means operably connected withthe multiple welding head means for providing a simultaneous sequentialwelding operation of the welding heads during a welding operation, andsaddle means secured to the track means and having one position forsecuring the track means around the pipe section in a manner precludingmovement of the track means and having a second position permittinglongitudinal movement of the track means along the outer periphery ofthe pipe section.
 2. A pipe welding apparatus as set forth in claim 1wherein the guide means includes a guide wheel rotatably secured to thesupport structure and engagable with the pipe joint during movement ofthe support apparatus around the pipe section, yieldable means connectedbetween the support apparatus and the guide wheel for constantly urgingthe wheel into engagement with the pipe joint, and slide meanscooperating between the guide wheel and welding head means formaintaining the guide wheel and welding head means in alignment with thepipe joint during movement of the support apparatus around the pipesection.
 3. A pipe welding apparatus as set forth in claim 2 andincluding locking means cooperating with the support structure and guidewheel for locking the guide wheel out of engagement with the pipe jointduring the longitudinal movement of the track means along the outerperiphery of the pipe section.
 4. A pipe welding apparatus as set forthin claim 1 wherein the track means comprises a sectional annular supportmember having the inner periphery thereof larger than the outerperiphery of the pipe section, hinge means connecting the support membersections together in said annular configuration, said hinge meansproviding alternate open positions and closed positions of the supportmember for facilitating transverse installation and removal of the trackmeans with respect to the pipe section, a pair of concentricallydisposed longitudinally extending cylindrical flanges provided on thesupport member to provide a track for receiving the carriage means, andring gear means provided on the support member for cooperation with thedrive means to provide said circumferential movement of the carriagemeans around the track means.
 5. A pipe welding apparatus as set forthin claim 4 wherein the carriage means comprises a support body member,first roller means adjustably secured to the support body member forengagement with one of said cylindrical flanges during movement of thecarriage means around the track means, second roller means adjustablysecured to the support body member for engagement with the other of saidcylindrical flanges during movement of the carriage means around thetrack means, said first and second roller means cooperating with saidcylindrical flanges for facilitating the circumferential movement of thecarriage around the track means and for retaining the carriage means onthe track means.
 6. A pipe welding apparatus as set forth in claim 1wherein the carriage means comprises a support body member, and rollermembers adjustably secured to the support body member for engagementwith the track means to facilitate circumferential movement of thecarriage means around thE track means.
 7. A pipe welding apparatus asset forth in claim 1 wherein the multiple welding head means comprises aplurality of welding heads independently mounted on the support means,angle adjusting means cooperating between the support means and thewelding heads for independent adjustment of the radially extendingangular position of each welding head with respect to the outerperiphery of the pipe section, longitudinal adjusting means cooperatingbetween the support means and the welding heads for independentadjustment of the longitudinal position of each welding head withrespect to the pipe section for alignment of each welding head with thepipe joint, and oscillating means cooperating between the support meansand welding heads for providing independent oscillation of each weldinghead in a direction substantially perpendicular with respect to theplane of the pipe joint.
 8. A pipe welding apparatus as set forth inclaim 7 wherein the welding heads are disposed in substantial mutuallinear alignment and in substantial linear alignment with the pipe jointfor simultaneous and sequential welding of the pipe joint.